A pumping unit is the most common ground equipment in an oil extraction equipment used in the oil field. The pumping unit realizes oil pumping by controlling a horse-head on a walking beam to move upward and downward. During the oil pumping, the balance between balance weights and the horse-head should be controlled. If unbalance occurs, energy of a dragging motor for dragging the walking beam will be lost. If the unbalance is serious, it may cause the horse-head out of control.
At present, the balance of the pumping unit is adjusted by increasing or decreasing the number of balance weights on the balancing element below the pumping unit. The method may have the following defects: first, balance weights are easy to lose; second, balance weights have to be transported manually, and the labor intensity is large; third, balance weight adjustment is not precise; and fourth, it is necessary to execute adjustment after shutting the machine down.
At present, there is still no effective method to realize balance adjustment conveniently and automatically.